Virtual machine management among networked servers

ABSTRACT

Virtual machine management among networked servers coupled for data communications with a data communications network that includes a network device and a Virtual Machine Management Module (‘VMMM’), where VM management includes: monitoring, by the network device, network traffic of applications executing in virtual machines of the servers; determining, in dependence upon the monitored network traffic, whether a particular application&#39;s network traffic exceeds a predetermined threshold, the particular application executing in a particular virtual machine of a particular server; if the particular application&#39;s network traffic exceeds the predetermined threshold, allocating, by the VMMM, an additional virtual machine in a different server; and instantiating, by the VMMM, in the additional virtual machine at least one application.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of and claims priorityfrom U.S. patent application Ser. No. 12/783,658, filed on May 20, 2010.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention is data processing, or, more specifically,methods, apparatus, and products for virtual machine management amongnetworked servers.

2. Description Of Related Art

The development of the EDVAC computer system of 1948 is often cited asthe beginning of the computer era. Since that time, computer systemshave evolved into extremely complicated devices. Today's computers aremuch more sophisticated than early systems such as the EDVAC. Computersystems typically include a combination of hardware and softwarecomponents, application programs, operating systems, processors, buses,memory, input/output devices, and so on. As advances in semiconductorprocessing and computer architecture push the performance of thecomputer higher and higher, more sophisticated computer software hasevolved to take advantage of the higher performance of the hardware,resulting in computer systems today that are much more powerful thanjust a few years ago.

Computer systems today are often networked for data communications andoften run several operating systems concurrently through the use ofvirtual machines—software emulating hardware. An application executingin a virtual machine of a server may, from time to time, receive or sendso many data communications packets or messages that the applicationeffectively monopolizes bandwidth available to the server upon which thevirtual machine and the application are executing. Other applicationsexecuting in the same or different virtual machine on the same servermay be unable to operate at high efficiency due to a lack of availablebandwidth. In addition, in some cases when one application receives agreat number of data communications messages, the application itself maybe overwhelmed.

SUMMARY OF THE INVENTION

Methods, apparatus, and products for virtual machine management amongnetworked servers are disclosed. In embodiments of the presentinvention, the servers are coupled for data communications with a datacommunications network that includes a network device and a VirtualMachine Management Module (‘VMMM’). Virtual machine management inaccordance with embodiments of the present invention includesmonitoring, by the network device, network traffic of applicationsexecuting in virtual machines of the servers; determining, in dependenceupon the monitored network traffic, whether a particular application'snetwork traffic exceeds a predetermined threshold, the particularapplication executing in a particular virtual machine of a particularserver. If the particular application's network traffic exceeds thepredetermined threshold, allocating, by the VMMM, an additional virtualmachine in a different server; and instantiating, by the VMMM, in theadditional virtual machine at least one application.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescriptions of exemplary embodiments of the invention as illustrated inthe accompanying drawings wherein like reference numbers generallyrepresent like parts of exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 sets forth a line drawing of an exemplary data center in whichvirtual machines are managed among networked servers according toembodiments of the present invention.

FIG. 2 sets forth a network diagram of an exemplary system for managingvirtual machines among networked servers according to embodiments of thepresent invention.

FIG. 3 sets forth a flow chart illustrating an exemplary method forvirtual machine management among networked servers according toembodiments of the present invention.

FIG. 4 sets forth a flow chart illustrating a further exemplary methodfor virtual machine management among networked servers according toembodiments of the present invention.

FIG. 5 sets forth a flow chart illustrating a further exemplary methodfor virtual machine management among networked servers according toembodiments of the present invention.

FIG. 6 sets forth a flow chart illustrating a further exemplary methodfor virtual machine management among networked servers according toembodiments of the present invention.

FIG. 7 sets forth a flow chart illustrating a further exemplary methodfor virtual machine management among networked servers according toembodiments of the present invention.

FIG. 8 sets forth a flow chart illustrating a further exemplary methodfor virtual machine management among networked servers according toembodiments of the present invention.

FIG. 9 sets forth a flow chart illustrating a further exemplary methodfor virtual machine management among networked servers according toembodiments of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary methods, apparatus, and products for virtual machinemanagement among networked servers in accordance with the presentinvention are described with reference to the accompanying drawings,beginning with FIG. 1. FIG. 1 sets forth a line drawing of an exemplarydata center in which virtual machines are managed among networkedservers according to embodiments of the present invention. A data center(120) is a facility used to house mission critical computer systems andassociated components. Such a data center may include environmentalcontrols (air conditioning, fire suppression, etc.), redundant/backuppower supplies, redundant data communications connections, and highsecurity, highlighted by biometric access controls to compartmentalizedsecurity zones within the facility. A data center may also house a largeamount of electronic equipment, typically computers and communicationsequipment. A data center may be maintained by an organization for thepurpose of handling the data necessary for its operations. A bank, forexample, may have a data center, where the bank customers' accountinformation is maintained and transactions involving these accounts arecarried out. Practically every company that is mid-sized or larger hassome kind of data center with the larger companies often having dozensof data centers.

A virtual machine (‘VM’) as the term is used in this specificationrefers to a software implementation of a machine, such as a computer. Avirtual machine enables sharing of the underlying physical machineresources between different virtual machines, each of which may run itsown operating system. The software layer providing the virtualization iscalled a virtual machine monitor or hypervisor. A hypervisor is a moduleof automated computing machinery that performs software and hardwareplatform-virtualization in order to enable multiple operating systems torun on a host computer concurrently in separate virtual machines. Ahypervisor runs directly on the host's hardware to control hardwareaccess and to monitor guest operating-systems. A guest operating systemruns on a level above the hypervisor. The platform virtualizationprovided by a hypervisor is referred to in this specification as avirtualized environment. A virtualized environment is one in whichphysical characteristics of a computing platform—computer processors,computer memory, I/O adapters, and the like—are abstracted from theperspective of an operating system and other software applications.

VMs provide many benefits including, for example:

-   -   multiple OS environments can co-exist on the same physical        computer hardware resources, in strong isolation from each        other;    -   an instruction set architecture (ISA) that is somewhat different        from that of the ISA of the underlying physical computer        hardware resources;    -   application provisioning, maintenance, high availability and        disaster recovery; and    -   other benefits as will occur to readers of skill in the art.

The example data center (120) in the example of FIG. 1 includes a bladecenter™ (100), a type of server chassis specifically configured to housea number of blade servers. A server, as the term is used in thisspecification, refers generally to a multi-user computer that provides aservice (e.g. database access, file transfer, remote access) orresources (e.g. file space) over a network connection. The term‘server,’ as context requires, refers inclusively to the server'scomputer hardware as well as any server application software oroperating system software running on the server. A server application isan application program that accepts connections in order to servicerequests from users by sending back responses. A server application canrun on the same computer as the client application using it, or a serverapplication can accept connections through a computer network. Examplesof server applications include file server, database server, backupserver, print server, mail server, web server, FTP servers, applicationservers, VPN servers, DHCP servers, DNS servers, WINS servers, logonservers, security servers, domain controllers, backup domaincontrollers, proxy servers, firewalls, and so on.

A blade server is a server computer with a modular design optimized tominimize the use of physical space and energy. Whereas a standardrack-mount server can function with at least a power cord and networkcable, blade servers have many components removed to save space,minimize power consumption and other considerations, while still havingall the functional components to be considered a computer. A bladecenter, which can hold multiple blade servers, provides services such aspower, cooling, networking, various interconnects and management—thoughdifferent blade providers have differing principles around what toinclude in the blade itself (and sometimes in the enclosure altogether).

In the example of FIG. 1, the blade center (100) includes two cabinetbays (104, 106), each of which includes several components. Cabinet bay(104) contains a number of blade servers (108), each of which is poweredby a power supply (132). Cabinet bay (106) contains the power supply(132) for the blade center (100), a data communications network router(130), a network switch (134), and a virtual machine management module(‘VMMM’) (102) which is described below in more detail. Cabinet bay(106) also contains a Redundant Array of Independent Disks (‘RAID’)(136) and a power strip (138).

In FIG. 1, two of the blade servers (108) in the blade center (100) aredepicted in an expanded form for clarity of explanation: blade server(152) and blade server (128). Readers of skill in the art willunderstand, however, that each of the blade servers (108) of the bladecenter (100) may include similar components to servers (152, 128) andoperate in a similar fashion when participating in VM management inaccordance with embodiments of the present invention. Consider, as anexample of server useful in systems in which VM management is carriedout in accordance with embodiments of the present invention, server(152). Server (152) includes at least one computer processor (156) or‘CPU’ as well as random access memory (168) (‘RAM’) which is connectedthrough a high speed memory bus (166) and bus adapter (158) to processor(156) and to other components of the server (152).

Stored in RAM (168) of the server (152) is a hypervisor (140) thatenables two virtual machines (114, 116) to run on the server's (152)underlying hardware and utilize the server's (152) hardware resources.Executing within (or said another way, ‘running on’) virtual machine(114), is an operating system (154) and two user-level applications(122, 123). Operating systems useful in servers that participate in VMmanagement according to embodiments of the present invention includeUNIX™, Linux™, Microsoft XP™, AIX™, IBM's i5/OS™, and others as willoccur to those of skill in the art. Executing within virtual machine(116) is an operating system (154) and two user-level applications (124,125). Operating system (154) executing within virtual machine (116) maybe a separate instance of the same operating system (154) executing invirtual machine (114), or may be another type of operating system (154)altogether. That is, both operating systems in server (152) may be thesame—such as Unix™—or both operating systems may be different—such asUnix™ and Microsoft XP™.

The hypervisor (140), operating systems (154), and user-levelapplications (122-125) in the example of FIG. 1 are shown in RAM (168),but many components of such software typically are stored innon-volatile memory also, such as, for example, on a disk drive (170).

The server (152) of FIG. 1 includes disk drive adapter (172) coupledthrough expansion bus (160) and bus adapter (158) to processor (156) andother components of the server (152). Disk drive adapter (172) connectsnon-volatile data storage to the server (152) in the form of disk drive(170). Disk drive adapters useful in servers that participate in virtualmachine management among networked servers according to embodiments ofthe present invention include Integrated Drive Electronics (‘IDE’)adapters, Small Computer System Interface (‘SCSI’) adapters, and othersas will occur to those of skill in the art. Non-volatile computer memoryalso may be implemented for as an optical disk drive, electricallyerasable programmable read-only memory (so-called ‘EEPROM’ or ‘Flash’memory), RAM drives, and so on, as will occur to those of skill in theart.

The example server (152) of FIG. 1 includes one or more input/output(‘I/O’) adapters (178). I/O adapters implement user-orientedinput/output through, for example, software drivers and computerhardware for controlling output to display devices such as computerdisplay screens, as well as user input from user input devices (181)such as keyboards and mice. The example server (152) of FIG. 1 includesa video adapter (209), which is an example of an I/O adapter speciallydesigned for graphic output to a display device (180) such as a displayscreen or computer monitor. Video adapter (209) is connected toprocessor (156) through a high speed video bus (164), bus adapter (158),and the front side bus (162), which is also a high speed bus.

The exemplary server (152) of FIG. 1 includes a communications adapter(167) for data communications with other computers and for datacommunications with a data communications network (not shown in FIG. 1).Such data communications may be carried out serially through RS-232connections, through external buses such as a Universal Serial Bus(‘USB’), through data communications networks such as IP datacommunications networks, and in other ways as will occur to those ofskill in the art. Communications adapters implement the hardware levelof data communications through which one computer sends datacommunications to another computer, directly or through a datacommunications network. Examples of communications adapters useful inservers that participate in VM management according to embodiments ofthe present invention include modems for wired dial-up communications,Ethernet (IEEE 802.3) adapters for wired data communications networkcommunications, and 802.11 adapters for wireless data communicationsnetwork communications.

Although only server (152) is depicted as including a processor (156),RAM (168), bus adapter (158), communications adapter (167) and the like,readers of skill in the art will recognize that any of the blade servers(108) in the example of FIG. 1 and, more specifically, server (128), mayalso include similar components. In the example of FIG. 1, server (128)is depicted as executing a hypervisor (142) that supports a virtualmachine (118) within which an operating system (154) and a user-levelapplication (126) are executing.

The switch (134) of the blade center (100) of FIG. 1 is an example of anetwork device, a unit that mediates data in a computer network.Networking devices may also be referred to as network equipment,Intermediate Systems (IS) or InterWorking Units (IWUs). Units which arethe last receiver or generate data are called hosts or data terminalequipment.

Examples of networking devices include:

-   -   Gateway: a device at a network node that interfaces with another        network that uses different protocols. Operates on Open System        Interconnection (‘OSI’) layers 4 to 7.    -   Router: a specialized network device that determines the next        network point to which to forward a data packet toward its        destination. Typically operates on OSI layer 3.    -   Bridge: a device that connects multiple network segments along        the data link layer. Operates on OSI layer 2.    -   Switch: a device that allocates traffic from one network segment        to certain lines or ‘links’—intended destination or destinations        which connect the segment to another network segment. Unlike a        hub, a switch splits the network traffic and sends it to        different destinations rather than to all systems on the        network. Operates on OSI layer 2.    -   Multilayer Switch: a switch which, in addition to switching on        OSI layer 2, provides functionality at higher protocol layers.    -   Hub: a device that connects multiple segments together and        operates them as if they were a single segment. When using a        hub, every attached device shares the same broadcast domain and        the same collision domain. Therefore, only one computer        connected to the hub is able to transmit at a time. Depending on        the network topology, the hub provides a level 1 OSI model        connection among the network objects (workstations, servers,        etc). The hub may also provide bandwidth that is shared among        all the objects, compared to switches, which provide a dedicated        connection between individual nodes. Operates on OSI layer 1.    -   Repeater: a device that amplifies or regenerates digital signals        received while setting the digital signals from one part of a        network into another. Operates on OSI layer 1.    -   Protocol Converter: a hardware device that converts between two        different types of transmissions, such as asynchronous and        synchronous transmissions.    -   Bridge Router: a device that operates in a combination of router        and bridge functionality. Operates on both OSI layer 2 and OSI        layer 3.    -   Digital media receiver: a device that connects a computer        network to a home theatre

The switch (134) in the example of FIG. 1, couples the blade servers(108, including 152 and 128) for data communications with one anotherand with the router (130) and the VMMM (102). The switch (134), inconcert with the virtual machine management module (102) as describedbelow, operates for VM management in accordance with embodiments of thepresent invention. The virtual machine management module (102) (‘VMMM’)of FIG. 1 is a module of automated computing machinery comprising anaggregation of computer hardware and software that is configured tomanage VMs among the networked servers (108 including 152 and 128) inthe example of FIG. 1. The VMMM (102) in the example of FIG. 1 isexecuting a VM allocator, a module of computer program instructions thatwhen executed causes the VMMM (102) to operate for VM management inaccordance with embodiments of the present invention.

The switch (134) may monitor network traffic of applications (122-126)executing in virtual machines (114, 116, 118) of the servers (152, 128).Network traffic refers to data communications among servers that issupported by a network device, the switch (134) of FIG. 1. Networktraffic may be quantified and monitored in various ways including, asone example, maintaining a count of a number of data communicationspackets originating from or transmitted to a particular applicationexecuting in a VM of a server. Here network traffic is monitored at theOpen System Interconnection (‘OSI’) Layer 7—the application layer—ratherthan a lower level. In this way, identifiers of particular instances ofapplications may be associated with network traffic statistics—number ofpackets per application, and the like.

As explained below in greater detail with respect to FIG. 2, FIG. 8, andFIG. 9 either the network switch (134) or the VMMM (102)—via the VMallocator (110)—may then determine, in dependence upon the monitorednetwork traffic (112), whether a particular application's (122-126)network traffic exceeds a predetermined threshold. If the particularapplication's (122-126) network traffic (112) exceeds the predeterminedthreshold the VM allocator (110) of the VMMM (102) may then allocate anadditional virtual machine (114, 116, 118) in a different server (152,128) and instantiate, by the VMMM (102), in the additional virtualmachine (114, 116, 118) at least one application (122-126). The term‘allocate’ is used here to indicate that a virtual machine isestablished and as such, resources of the underlying server are providedto, that is allocated to, the virtual machine in some fashion.

Consider, as an example of VM management carried out among the servers(108) of FIG. 1 that the monitored network traffic, as described by theapplication traffic statistics (112), of user-level application (122)executing within the virtual machine (114) of server (152), exceeds thepredetermined threshold. In such an example, the VM allocator (110) ofthe VMMM (102) may allocate an additional VM, such as the VM (118) ofserver (128), and instantiate at least one application, such asuser-level application (126), in the VM (118) of the server (128). Aspart of allocating the virtual machine, the VM allocator (110) of theVMMM (102) may also execute the hypervisor (142) if no hypervisor waspreviously executing and the VM allocator (110) may also boot load anoperating system (154) prior to instantiating the user-level application(126). The user-level application (126) may be any of:

-   -   another instance of the user-level application (122) that runs        concurrently with the user-level application (122). In this        example, user-level application (126) operates as a duplicate of        the application (122) to distribute data communications amongst        both the servers (152, 128) rather than just server (152);    -   another instance of the user-level application (122) that does        not run concurrently with the user-level application (122)—In        this example, application (122) has been effectively ‘moved’        from server (152) to server (128), freeing bandwidth to other        user-level applications (123-125) executing on server (152).    -   an instance of another user-level application (123-125)        executing on server (152). In this example, the other user-level        application (123-125) may effectively be moved, or duplicated,        on a different server so as to provide the other user-level        application (123-125) with available bandwidth;    -   others as will occur to readers of skill in the art.

The arrangement of servers and other devices making up the exemplarysystem illustrated in FIG. 1 are for explanation, not for limitation.Data processing systems useful according to various embodiments of thepresent invention may include additional servers, routers, otherdevices, and peer-to-peer architectures, not shown in FIG. 1, as willoccur to those of skill in the art. Networks in such data processingsystems may support many data communications protocols, including forexample TCP (Transmission Control Protocol), IP (Internet Protocol),HTTP (HyperText Transfer Protocol), WAP (Wireless Access Protocol), HDTP(Handheld Device Transport Protocol), and others as will occur to thoseof skill in the art. Various embodiments of the present invention may beimplemented on a variety of hardware platforms in addition to thoseillustrated in FIG. 1.

FIG. 2 sets forth a network diagram of an exemplary system for managingvirtual machines among networked servers according to embodiments of thepresent invention. The exemplary system of FIG. 2 is similar to thesystem depicted in the example of FIG. 1 in that the system of FIG. 2also includes servers (152, 128), a network device in the form of aswitch (134), and a VMMM (102), all of which are coupled or datacommunications with one another via a data communications network, alocal area network (‘LAN’) (101). The servers (152, 128) and VMMM (102)are also coupled to other servers (150) for data communications.

In the system of FIG. 2, the servers (152, 128, and 150) are implementedas computers that include similar components—processor (156), RAM (168),bus adapter (158), communications adapter (178), and the like—as theservers depicted in, and described with respect to, FIG. 1. The switch(134), in the example of FIG. 2, is also implemented as a type ofcomputer, that is, automated computing machinery, similar to the servers(152, and 128). The switch (134) includes a processor (156) coupled toRAM (168). The switch, of course, may include more components, softwareand hardware, but for clarity of explanation is depicted in the exampleof FIG. 2 with only RAM and a processor. Stored in RAM (168) of theswitch (134) is a traffic monitor (202). A traffic monitor (202) is amodule of computer program instructions that when executed cause thenetwork switch (134) to monitor network traffic (144, 146, 148) ofapplications (122-126) executing in virtual machines (114,116, 128) ofthe servers (150, 152, 128). The example traffic monitor (202) storesapplication traffic statistics (112) in a management information base(‘MIB’) (204). Application traffic statistics (112) are informationdescribing applications' data communication traffic—data communicationsto and from an application. In the system of FIG. 2, the switch (134)executes a notification engine (206) along with the traffic monitor(202). The notification engine (206) is a module of computer programinstructions that when executed operates the switch (134) to performdetermine whether a particular application's network traffic exceeds apredetermined threshold and notifying the VMMM (102) if theapplication's network traffic does exceed the predetermined threshold(208).

An MIB is a virtual database used for managing the entities in acommunications network. The database is hierarchical (tree-structured)and entries are addressed through object identifiers. Internetdocumentation Request For Comments (‘RFCs’) discuss MIBs, notably RFC1155, “Structure and Identification of Management Information for TCP/IPbased internets,” and its two companions, RFC 1213, “ManagementInformation Base for Network Management of TCP/IP-based internets,” andRFC 1157, “A Simple Network Management Protocol.” In this example, theMIB also stores application traffic statistics describing applications'data communication traffic.

In addition to the switch (134), and as mentioned above with respect toFIG. 1, the VMMM (102) may also be implemented as automated computingmachinery—that is, as a computer. For further explanation, therefore,FIG. 2 sets forth an example VMMM (102) implemented as a computer. Theexample VMMM (102) of FIG. 2 includes components similar to those of theservers (152, 128): a processor (156), a bus adapter (158), acommunications adapter (178), RAM (168), and so on. Stored in RAM (168)of the VMMM (102) is a virtual machine allocator (110). The VM allocator(110) is a module of computer program instructions that when executedmanages virtual machines among networked servers in accordance withembodiments of the present invention. As an alternative to thenotification engine (206) of the switch, the VM allocator (110) of theVMMM (102) may also be configured to determine whether a particularapplication's (122-126) network traffic exceeds a predeterminedthreshold (208). That is, either of the switch (134) or the VMMM (102)may determine whether an application's network traffic exceeds athreshold. In this way, the hypervisors (140, 142) supporting thevirtual machines (114, 116, 118) in which the applications (122-126)execute, need not dedicate processing overhead to monitoring the datacommunications and determining whether an application's network trafficexceeds a threshold. Such an embodiment would decrease resourcesavailable to the application during the time the hypervisor ismonitoring network traffic and determining whether the network trafficexceeds a threshold.

In the system of FIG. 2, if the particular application's (122-126)network traffic (146, 148, 144) exceeds the predetermined threshold(208) the VM allocator (110) of the VMMM (102) allocates an additionalvirtual machine (114, 116, 118) in a different server (152, 128) andinstantiates in the additional virtual machine (114, 116, 118) at leastone application.

The arrangement of servers and other devices making up the exemplarysystem illustrated in FIG. 2 are for explanation, not for limitation.Data processing systems useful according to various embodiments of thepresent invention may include additional servers, routers, otherdevices, and peer-to-peer architectures, not shown in FIG. 2, as willoccur to those of skill in the art. Networks in such data processingsystems may support many data communications protocols, including forexample TCP (Transmission Control Protocol), IP (Internet Protocol),HTTP (HyperText Transfer Protocol), WAP (Wireless Access Protocol), HDTP(Handheld Device Transport Protocol), and others as will occur to thoseof skill in the art. Various embodiments of the present invention may beimplemented on a variety of hardware platforms in addition to thoseillustrated in FIG. 2.

For further explanation, FIG. 3 sets forth a flow chart illustrating anexemplary method for virtual machine management among networked serversaccording to embodiments of the present invention. In the method of FIG.3, the servers (312, 324, 332) are coupled for data communications (322)with a data communications network that includes a network device (310)and a VMMM (102).

The method of FIG. 3 includes monitoring (302), by the network device(310), network traffic (322) of applications (314, 318, 326) executingin virtual machines (316, 320) of the servers (312, 324). Monitoring(302), by the network device (310), network traffic (322) ofapplications (314, 318, 326) executing in virtual machines (316, 320) ofthe servers (312, 324) may be carried out by maintaining a count of datacommunications packets from and to (or any combination thereof) aparticular application.

The method of FIG. 3 also includes determining (304), in dependence uponthe monitored network traffic (322), whether a particular application's(314) network traffic (112) exceeds a predetermined threshold (208).Determining (304) whether a particular application's (314) networktraffic (112) exceeds a predetermined threshold (208) may be carriedout, periodically for each currently executing application, by comparingthe number of packets received from and sent to that application sincethe last determination was made to the predetermined threshold. In themethod of FIG. 3, the particular application (314) executes in aparticular virtual machine (316) of a particular server (312). The term‘particular’ here is used only for ease of explanation in identifyingthe application presently at issue, the virtual machine within which theapplication at issue executes and the server upon which the virtualmachine within which the application at issue executes runs.

If the particular application's (314) network traffic (112) does notexceed the predetermined threshold (208), the method of FIG. 3 continuesby waiting (330) a predefined amount of time before again determining(304) whether the particular application's (314) network traffic (112)exceeds the predetermined threshold (208). That is, the switch (134) orVMMM (102), whichever is configured to carry out the determination step(304), may be configured to periodically determine whether anapplications' traffic is greater than the predetermined threshold.

If the particular application's (314) network traffic (112) exceeds thepredetermined threshold (208), the method of FIG. 3 continues byallocating (306), by the VMMM (102), an additional virtual machine (336)in a different server (332). Allocating (306), by the VMMM (102), anadditional virtual machine (336) in a different server (332) may becarried out by staring a hypervisor in the different server (332),providing to the hypervisor a virtual machine configuration specifyingvarious attributes, such as CPU type, available memory, I/O devices, andother hardware resources, instructing the hypervisor to start thevirtual machine, and loading, as part of the VM's startup, an operatingsystem.

The method of FIG. 3 also includes instantiating (308), by the VMMM(102), in the additional virtual machine (336) at least one application(334). Instantiating (308) at least one application (334) in theadditional virtual machine (336) may be carried out by identifying theapplication, locating an executable in a repository of executables, adirectory structure of the particular server, and the like, supplyingthe executable file to the different server (332), and executing theexecutable file in the additional VM (336).

For further explanation, FIG. 4 sets forth a flow chart illustrating afurther exemplary method for virtual machine management among networkedservers according to embodiments of the present invention. The method ofFIG. 4 is similar to the method of FIG. 3 in that in the method of FIG.4 the servers (312, 324, 332) are coupled for data communications (322)with a data communications network that includes a network device (310)and a VMMM (102). The method of FIG. 4 is also similar to the method ofFIG. 3 in that the method of FIG. 4 includes monitoring (302), networktraffic (322) of applications (314, 318, 326); determining (304) whethera particular application's (314) network traffic (112) exceeds apredetermined threshold (208); allocating (306) an additional virtualmachine (336) in a different server (332) if the particularapplication's (314) network traffic (112) exceeds the predeterminedthreshold (208); and instantiating (308) at least one application (334)in the additional virtual machine (336).

The method of FIG. 4 differs from the method of FIG. 3, however, inthat, in the method of FIG. 4, instantiating (308) at least oneapplication (334) in the additional virtual machine (336) is carried outby moving (402) the particular application (314) from the particularvirtual machine (316) of the particular server (312) to the additionalvirtual machine (336) of the different server (332). Moving (402) theparticular application (314) may be carried out in various ways,including, for example by providing to the additional virtual machine(336) a copy of an executable file of the particular application (314),executing the copy of the executable file, and stopping execution of theparticular application (314) on the particular server. The term ‘moving’is used here to describe an effect or an outcome rather than the meansby which an application is moved. That is, movement of an applicationdescribes two states of an application, a first state in which anapplication is executing on a particular server, and a final state inwhich the application is no longer executing on that particular serverbut is instead executing on another server. From the first state to thesecond state, therefore, one may describe the application as having been‘moved’ from the particular server to the other server. The means bywhich such a ‘movement’ of an application is carried out, however, mayvary greatly within the scope of the present invention. In the method ofFIG. 4, the particular application (314) is moved form the particularserver (312) to the different server (312) to reduce the datacommunications received by or sent from the particular server (312).That is, another application (318) executing in another virtual machine(320) or even the same particular VM (316) as the particular application(314) may have little to no available bandwidth (due to the particularapplication's massive bandwidth usage) before the movement of theparticular application (314), but after the movement, the application(318) may have more available bandwidth due to the reduction in theparticular application's massive bandwidth usage.

For further explanation, FIG. 5 sets forth a flow chart illustrating afurther exemplary method for virtual machine management among networkedservers according to embodiments of the present invention. The method ofFIG. 5 is similar to the method of FIG. 3 in that in the method of FIG.5 the servers (312, 324, 332) are coupled for data communications (322)with a data communications network that includes a network device (310)and a VMMM (102). The method of FIG. 5 is also similar to the method ofFIG. 3 in that the method of FIG. 5 includes monitoring (302), networktraffic (322) of applications (314, 318, 326); determining (304) whethera particular application's (314) network traffic (112) exceeds apredetermined threshold (208); allocating (306) an additional virtualmachine (336) in a different server (332) if the particularapplication's (314) network traffic (112) exceeds the predeterminedthreshold (208); and instantiating (308) at least one application (334)in the additional virtual machine (336).

The method of FIG. 5 differs from the method of FIG. 3, however, inthat, in the method of FIG. 5, instantiating (308) at least oneapplication (334) in the additional virtual machine (336) is carried outby executing (502) a second instance of the particular application (314)in the additional virtual machine (336) of the different server (332)without halting execution of a first instance of the particularapplication (314) executing on the particular server (312). That is, inthe method of FIG. 5, the VMMM (102) executes another instance of thesame application (314) thereby distributing data communications (theapplications' network traffic) among both instances of the application.Consider, for example, that the particular application (314) is aprinter server, receiving a great number of print requests. To reducethe data communications received by the particular server (312) directedto the printer server, the VMMM (102) may execute another instance ofthe printer server on a different server (332) such that print requestsmay be distributed among both the particular server (312) and thedifferent server (332).

For further explanation, FIG. 6 sets forth a flow chart illustrating afurther exemplary method for virtual machine management among networkedservers according to embodiments of the present invention. The method ofFIG. 6 is similar to the method of FIG. 3 in that in the method of FIG.6 the servers (312, 324, 332) are coupled for data communications (322)with a data communications network that includes a network device (310)and a VMMM (102). The method of FIG. 6 is also similar to the method ofFIG. 3 in that the method of FIG. 6 includes monitoring (302), networktraffic (322) of applications (314, 318, 326); determining (304) whethera particular application's (314) network traffic (112) exceeds apredetermined threshold (208); allocating (306) an additional virtualmachine (336) in a different server (332) if the particularapplication's (314) network traffic (112) exceeds the predeterminedthreshold (208); and instantiating (308) at least one application (334)in the additional virtual machine (336).

The method of FIG. 6 differs from the method of FIG. 3, however, inthat, in the method of FIG. 6, instantiating (308) at least oneapplication (334) in the additional virtual machine (336) is carried outby moving (602) another application (318) executing on a virtual machine(320) of the particular server (320) to the additional virtual machine(336) of the different server (332). In this way, applications otherthan the particular application executing on the same server as theparticular application monopolizing available bandwidth of the server,may be moved to another server thereby providing the other applicationaccess to bandwidth resources. Although the application (318) moved fromthe particular server (312) to the different server (332) in the exampleof FIG. 6, is depicted as executing in a different VM (320) than theparticular application (314), such is not a limitation. Instead, anyapplication executing on the same server (312) as the particularapplication (314) may be moved to the different server (332) inaccordance with embodiments of the present invention regardless of theVM of the server (312) in which the application is executing.

For further explanation, FIG. 7 sets forth a flow chart illustrating afurther exemplary method for virtual machine management among networkedservers according to embodiments of the present invention. The method ofFIG. 7 is similar to the method of FIG. 3 in that in the method of FIG.7 the servers (312, 324, 332) are coupled for data communications (322)with a data communications network that includes a network device (310)and a VMMM (102). The method of FIG. 7 is also similar to the method ofFIG. 3 in that the method of FIG. 7 includes monitoring (302), networktraffic (322) of applications (314, 318, 326); determining (304) whethera particular application's (314) network traffic (112) exceeds apredetermined threshold (208); allocating (306) an additional virtualmachine (336) in a different server (332) if the particularapplication's (314) network traffic (112) exceeds the predeterminedthreshold (208); and instantiating (308) at least one application (334)in the additional virtual machine (336).

The method of FIG. 7 differs from the method of FIG. 3, however, inthat, in the method of FIG. 7, instantiating (308) at least oneapplication (334) in the additional virtual machine (336) is carried outby executing (702) a second instance of another application (318)executing on a virtual machine of the particular server in theadditional virtual machine of the different server without haltingexecution of a first instance of the another application on theparticular server. Here, the “another application” (318) executing onthe same server (312) of the particular application (314), iseffectively duplicated and executes on a different server (332). In thisway, data communications to and from the “another application” (318) maybe distributed among the two servers (312, 332) and the network trafficto and from the particular application (314) will affect the networktraffic of the “another application” (318) less than if only oneinstance of the “another application” (318) were executing on a server,especially if that server is the same server (312) upon which theparticular application (314) is executing.

For further explanation, FIG. 8 sets forth a flow chart illustrating afurther exemplary method for virtual machine management among networkedservers according to embodiments of the present invention. The method ofFIG. 8 is similar to the method of FIG. 3 in that in the method of FIG.8 the servers (312, 324, 332) are coupled for data communications (322)with a data communications network that includes a network device (310)and a VMMM (102). The method of FIG. 8 is also similar to the method ofFIG. 3 in that the method of FIG. 8 includes monitoring (302), networktraffic (322) of applications (314, 318, 326); determining (304) whethera particular application's (314) network traffic (112) exceeds apredetermined threshold (208); allocating (306) an additional virtualmachine (336) in a different server (332) if the particularapplication's (314) network traffic (112) exceeds the predeterminedthreshold (208); and instantiating (308) at least one application (334)in the additional virtual machine (336).

The method of FIG. 8 differs from the method of FIG. 3, however, inthat, in the method of FIG. 8, determining (304) whether a particularapplication's (314) network traffic (112) exceeds a predeterminedthreshold (208) is carried out by the network device (310) rather thanthe VMMM (102). The method of FIG. 8 also includes notifying, by thenetwork device (310), the VMMM (102) that the particular application's(314) network traffic (322) as expressed in the particular application'straffic statistics, is greater than the predetermined threshold.

In the method of FIG. 8, allocating (306) an additional virtual machine(336) in a different server (332) if the particular application's (314)network traffic (112) exceeds the predetermined threshold (208) iscarried out by allocating (804) the additional virtual machine onlyafter receiving, by the VMMM (102), a notification from the networkdevice that the particular application's network traffic exceeds thepredetermined threshold.

For further explanation, FIG. 9 sets forth a flow chart illustrating afurther exemplary method for virtual machine management among networkedservers according to embodiments of the present invention. The method ofFIG. 9 is similar to the method of FIG. 3 in that in the method of FIG.9 the servers (312, 324, 332) are coupled for data communications (322)with a data communications network that includes a network device (310)and a VMMM (102). The method of FIG. 9 is also similar to the method ofFIG. 3 in that the method of FIG. 9 includes monitoring (302), networktraffic (322) of applications (314, 318, 326); determining (304) whethera particular application's (314) network traffic (112) exceeds apredetermined threshold (208); allocating (306) an additional virtualmachine (336) in a different server (332) if the particularapplication's (314) network traffic (112) exceeds the predeterminedthreshold (208); and instantiating (308) at least one application (334)in the additional virtual machine (336).

The method of FIG. 9 differs from the method of FIG. 3, however, inthat, in the method of FIG. 9, determining (304) whether a particularapplication's (314) network traffic (112) exceeds a predeterminedthreshold (208) is carried out by querying (902) the network device(310) by the VMMM (102) for information describing the monitored networktraffic and determining (904), by the VMMM (102) in dependence upon theretrieved information (112), whether the particular application'snetwork traffic exceeds a predetermined threshold (208). FIG. 9 setsforth an alternative way of carrying out the determination (304) stepwith regard to the method of FIG. 8. In FIG. 9, the VMMM (102) makes thedetermination (304), while in FIG. 8 the network device (310) carriesout the determination.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described above with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

It will be understood from the foregoing description that modificationsand changes may be made in various embodiments of the present inventionwithout departing from its true spirit. The descriptions in thisspecification are for purposes of illustration only and are not to beconstrued in a limiting sense. The scope of the present invention islimited only by the language of the following claims.

What is claimed is:
 1. A method of virtual machine management amongnetworked servers, the servers coupled for data communications with adata communications network that includes a network device and a VirtualMachine Management Module (‘VMMM’), the method comprising: monitoring,by the network switch, network traffic of a first user-level applicationincluding monitoring bandwidth used by the first user-level application,wherein the first user-level application is one of a plurality ofuser-level applications executing in virtual machines of the servers,wherein the network switch is separate from the servers and coupled tothe servers via the data communications network, and wherein the networktraffic is monitored by the network switch at an application layer;determining, by the network switch, in dependence upon the monitorednetwork traffic, whether the first user-level application's networktraffic exceeds a predetermined threshold, the first user-levelapplication executing in a particular virtual machine of a particularserver, wherein the first user-level application exceeding thepredetermined threshold indicates that a second user-level applicationon the particular server has insufficient bandwidth; if the firstuser-level application's network traffic exceeds the predeterminedthreshold, allocating, by the VMMM, an additional virtual machine in adifferent server including allocating the additional virtual machineonly after receiving, by the VMMM via the data communications network, anotification from the network switch that the first user-levelapplication's network traffic exceeds the predetermined threshold; andinstantiating, by the VMMM, in the additional virtual machine at leastone user-level application, wherein instantiating the at least oneuser-level application comprises: moving the particular first user-levelapplication from the particular virtual machine of the particular serverto the additional virtual machine of the different server; and providingthe second user-level application with sufficient bandwidth in responseto moving the first user-level application.
 2. The method of claim 1wherein, instantiating at least one user-level application furthercomprises executing a second instance of the first user-levelapplication in the additional virtual machine of the different serverwithout halting execution of a first instance of the first user-levelapplication executing on the particular server.
 3. The method of claim 1wherein, instantiating at least one user-level application furthercomprises moving another user-level application executing on a virtualmachine of the particular server to the additional virtual machine ofthe different server.
 4. The method of claim 1 wherein, instantiating atleast one user-level application further comprises executing a secondinstance of another user-level application executing on a virtualmachine of the particular server in the additional virtual machine ofthe different server without halting execution of a first instance ofthe another user-level application on the particular server.
 5. Themethod of claim 1 wherein determining whether a first user-levelapplication's network traffic exceeds a predetermined threshold furthercomprises: querying the network switch by the VMMM for informationdescribing the monitored network traffic; and determining, by the VMMMin dependence upon the retrieved information, whether the firstuser-level application's network traffic exceeds a predeterminedthreshold.
 6. A method for virtual machine management among networkedservers, the servers coupled for data communications with a datacommunications network that includes a network switch and a VirtualMachine Management Module (‘VMMM’), the method comprising: monitoringnetwork traffic by the network switch including: monitoring bandwidthused by a first user-level application, wherein the first user-levelapplication is one of a plurality of user-level applications executingin virtual machines of the servers, monitoring bandwidth used by asecond user-level application, wherein the second user-level applicationis one of the plurality of user-level applications executing in thevirtual machines of the servers, wherein the network switch is separatefrom the servers and coupled to the servers via the data communicationsnetwork, and wherein the network traffic is monitored by the networkswitch at an application layer; determining, by the network switch, independence upon the monitored network traffic, that the first user-levelapplication's network traffic exceeds a predetermined threshold, thefirst user-level application executing in a particular virtual machineof a particular server, wherein the first user-level applicationexceeding the predetermined threshold indicates that the seconduser-level application on the particular server has insufficientbandwidth; notifying, by the network switch, the VMMM that the firstuser-level application's network traffic exceeds the predeterminedthreshold; in response to the notification that first user-levelapplication's network traffic exceeds the predetermined threshold,allocating, by the VMMM, an additional virtual machine in a differentserver including allocating the additional virtual machine only afterreceiving, by the VMMM via the data communications network, anotification from the network switch that the first user-levelapplication's network traffic exceeds the predetermined threshold; andinstantiating, by the VMMM, in the additional virtual machine at leastone user-level application, wherein instantiating the at least oneuser-level application further comprises: moving the particular firstuser-level application from the particular virtual machine of theparticular server to the additional virtual machine of the differentserver; and providing the second user-level application with sufficientbandwidth in response to moving the first user-level application.